Vernier control



Dec. 12, 1939. LA 2,182,961

- VERNIER CON'IIROL Filed Nov'. 6, 1937 INVENTOR ROY T. CLAY.

ATTORNEY Patented Dec. 12, 1939 PATENT OFFICE VERNIER CONTROL oy '1'. Clay, Buffalo, N. "1., assignor to Curtisv,

Wright Corporation, a corporation of Dela- Appiication November 6, 1937, Serial No. 173,173

3Claim8.

This invention relates to adjustable control levers, providing particularly an improved means for. eflecting small and accurate changes in the position of a control lever with respect to a & quadrant associated therewith.

An object of the invention is to provide. an easily operated vernier control for a control lever.

A further object is to provide, in one embodiment, a single knob on a control lever operable iii to shift the lever over a wide range of adjustment to obtain coarse adjustments, and by further manipulation of the same control knob, to eflectfine positioning of the lever.

Another object is to provide, in an alternative 35 embodiment, vernier control means which may be actuated in any position of adjustment of the control lever, but which does not interfere with the operation of the lever for coarse adjustment.

Further objects will be apparent from a readan ing of the annexed specification and claims, to-

gether with an examination of the accompanying drawing, in which:

Fig. 1 is a side elevation of a quadrant and lever assembly embodying one form of the ingg vention;

Fig. 2 is a plan view of'Fig. 1;

Fig.6 is an elevation of an alternative embodiment, and

Fig. 4 is-a plan view of the embodiment of m Fi 3.

First referring to Figs. 1 and 2, I show a composite control quadrant 9 provided with a plurality of slots Iii to i5, inclusive, within each of I which levers 16 to i9, inclusive, are engaged, re- 35 spectively operating control rods 20 to 25, inclusive, in the conventional manner, An assembly of this character is useful in aircraft in pro-'.

viding a unitary device by which a plurality of engine control levers are incorporated, such con- 40 trols comprising the engine throttle, the carburetor mixture control, the spark advance, and. the control for 'a constant speed controllable pitch propeller. The provisions of this invention are particularly adapted for the latter con- 45 trol, which is, as shown, the-control lever 11. The quadrant 26 for the lever I1 is provided with index markings indicating engine revolutions and, by means which do not form a part of this particular invention, movements of the lever i1 5 are transmitted to thepropeller control unit by which the governor thereof is pre-set to desired R. P. M}. In the quantitative adjustment of the several power plant controls, it is dwirable to accurately set the controls and particularly the ;-propeller speed control, within accurate quantitative limits and, since a simple lever organization is difficult to control closely, means are provided for effecting a "vernier adjustment of the lever l1. These means comprise a toothed rack 21 either attachedto or integral with the quadrant 26, the teeth of the rack taking theform of bevel gear teeth. .The lever H is provided with angular ofisets 2B and 29 drilled to limit the inward movement of the spindle. A

spring 34 embraces the spindle 30, hearing at one end upon the bracket 29, and at its other end upon a collar 35 fixed to the spindle, this spring normally urging the spindle pinion and knob assembly radially outward.

In operation, the knob 32 is used for directly g swinging the lever Lover the quadrant 28 to approximately the position desired. Then, the knob 32 may be pressed inwardly, engaging the pinion 3i with the rack 27, whereupon the knob 32 may be rotated in the appropriate direction to effect the fine adjustment necessary. The point 33 on the bevel pinion serves as an index mark for the lever which may be brought opposite the appropriate R. P. M. mark on the scale of the quadrant. 35

Referring to Figs. 3 and 4, I show an alternative arrangement wherein a quadrant has formed thereon a spur rack 4|, a lever 42 having a knob 43 engaging the quadrant and being movable thereover. The lever isprovided with a 40 bracket 44 providing a bearing for a pinion 45 engaging the rack 4|, the pinion shaft carrying a vernier knob 46 in a position readily accessible to the operator. Due to the spur gear and pinion'arrangement, the vernier control is revers- 45 ible so that direct control movements for coarse adjustment maybe effected by movement of the knob 43 and the lever 42 directly. Thereafter, aftercoarse adjustment has been obtained, the knob 46 may be rotated to effect the fine adjust- 5o ment desired.

It is known that in the prior art, vernier control adjustments have been provided, these no mally taking the form of worms engaging suitable teeth on a quadrant. provision being made.

for turning the worm for fine adjustment, utilizing the worm as a pawl or lock to prevent movement of a control lever inadvertently. In the particular environment for which the subject device is adapted, locking of the control lever with respect to the quadrant is unnecessary, and the irreversible control afforded by prior art devices is undesirable, since friction means are used to retain the lever in position, the friction means offering sufiicient drag so that the lever is retained in position but is susceptible to control movement by the operator without undue effort. Accordingly, reversibility of the Vernier adjustment is a desired function, since the Vernier adjustment need serve no locking purpose.

The devices described above have been embodied in, and have been found particularly useful in controls in a considerable number of aircraft.

While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications and changes,

I claim as my invention:

1. An, adjustable control assembly comprising 'a slotted quadrant having gear teeth along a rim face thereof, a control lever pivotally movable relative to said quadrant and passing through said slot, a bracket on the lever, a spindle rotatable and slidablein said bracket having a pinion engageable,-when said spindle is slid inwardbearings, rotatable and slidable relative thereto, 10

a bevel pinion on the inner end of said spindle and a knob on the outer end thereof, said bevel pinion being turnable and engageable with said rack by manipulation of said knob for finely adjusting the lever, the knob being directly movl5 able when the pinion is disengaged from said rack to move said lever in said quadrant for coarse adjustment.

3. An adjustable control assembly comprising a quadrant having a bevel toothed rack disposed at a rim face thereof, a control lever engaged with said quadrant, substantially radially alined hearings on said lever, a spindle engaged in said bearings, rotatable and slidable relative thereto, a bevel pinion on the inner end of said spindle and a knob on the outer end thereof, said bevel pinion being turnable and engageable with said rack by manipulation of said knob for finely ad- 'justing the lever, the knob being directly movable when the pinion is disengaged from said rack, to move said lever in said quadrant for coarse adjustment, and resilient means urging said pinion to a rack-disengaging position.

ROY T. CLAY. 

